Edit: this was written immediately following post #39 (by Karma Tennis), but wasn't submitted until ~90 minutes later. Other posts were submitted during this time period.
@KaiserW,
I was just about to ask if you had already tried
thoroughly cleaning the rails
and the
bottoms of both base clamps with 91% isopropyl alcohol?
However,
@Karma Tennis has already beaten me to that train of thought.
Since the
upper side of the rails directly contact the
bottoms of the base clamps, you need to be sure that both surfaces are well cleaned. I mention this because a lot of people will only wipe down the rails, not really thinking that the bottoms of the base clamps would have much of anything on them - but they do.
If you're lucky, this thorough cleaning
may just solve your problem (after all, you didn't have this slipping problem 6 weeks ago... or 2-3 months ago, right?)
Also,
@10shoe pointed out some key factors... you are putting additional strain on the bases (and actual string clamps too, for that matter) by starting your mains with that method in your video. As
@10shoe advised, try tensioning at least 2 mains on one side before beginning to tension a main on the opposite side. By doing this, the clamps/bases have much less strain put on them to maintain things - because the multiple "u-turns", that the string makes through the frame, creates additional friction points that would actually help you out (when you go to apply tension on the other side).
The method you're employing is only giving you
one "u-turn" (at the bridge/throat), and that really isn't enough friction points to help counter whatever tension is being applied at the gripper/tensioner.
1. Exactly what tension do you have your machine set at?
2. What kind of string on you using (i.e. is it a very slippery string to begin with)?
3. What gauge is that string (the thinner it is, the easier it is for it to slide around those "u-turns")?
4. Do you have a starting clamp?
If you have a starting clamp, you could use it to help prevent the two clamps from moving toward one another (that is,
if you're going to choose to continue using the method in the video).
Here's how...
After tensioning, and clamping, that first string (1MR) you would place the starting clamp on that
same string (at the head of the racquet, outside the frame)
before you release the string from the gripper/tensioner. Then, when you pulled tension on that second string (1ML) nothing would move.
The two clamps moving towards one another (at 0:54 in the video) is only made possible because the first string (1MR) is able to slide
freely through it's grommet at the
head of the frame. Placing a starting clamp on that string, outside the frame, would prevent the string from moving through the grommet - and therefore the clamps (and bases) would no longer be able to migrate towards each other (when you then applied tension to 1ML).
Nonetheless, I still think you should adopt a better method of starting your mains, that doesn't create as much undo strain in the first place.
Keep us updated as you work through the various suggestions.
Good luck.